JP6842991B2 - Helmet - Google Patents

Description

The present invention relates to a helmet comprising an outer cap body made of a hard material and a shock absorbing liner arranged inside the outer cap body.

Safety helmets such as open-face type and full-face type have been conventionally known as helmets worn by riders such as motorcycles to protect their heads. Such conventional helmets are mainly composed of an outer cap body, a shock absorbing liner arranged inside the cap body, a pair of left and right ago straps, and an interior pad for improving the wearing comfort of the wearer. It is composed of. Further, in order to secure the view of the wearer, a through hole for ventilation is provided in the upper part of the opening window provided on the front surface of the helmet.

When an impact is applied to a part of the outer cap body, the cap body disperses the impact over a wider region and absorbs the impact energy by its deformation. In addition, the shock absorbing liner absorbs the shock energy propagated from the outer cap body by reducing its thickness (that is, compression), and delays the shock energy from propagating to the wearer's head. By making it work, it works to reduce the maximum acceleration due to the above impact. Here, the above-mentioned "maximum acceleration" means the maximum value of acceleration obtained by the "shock absorption test" of the helmet.

Traditionally, "shock absorption tests" have been conducted to confirm the protective performance of safety helmets. In this "shock absorption test", a metal head model is used as a model of the helmet wearer's head. Then, the impact given to the helmet by the "shock absorption test" is absorbed as described above, and the acceleration is arranged inside the metal head model as the impact force finally propagated to the head. The maximum acceleration is measured by the meter. The method of such "shock absorption test" and the reference value of the maximum acceleration are set in each country.

In order to improve the protection performance of the safety helmet, it is necessary to reduce the maximum acceleration due to impact. For this reason, conventionally, measures have been taken to increase the thickness of the outer cap body and the shock absorbing liner.

However, since the helmet has a substantially spherical shape, the rigidity of the crown is inevitably higher than that of other parts, and it becomes difficult to absorb the impact. Therefore, a structure called an insert liner was invented.

In Patent Document 1 below, a cavity is provided in the inner crown of the shock absorbing liner, and another member is inserted therein. Since the inserted member (called an insert liner) has a lower density than the shock absorbing liner, that is, is soft, the rigidity of the crown can be reduced. In this way, the shock absorption of the crown can be maintained.

Japanese Patent No. 3825106

In recent traffic accidents, riders have been seen to suffer diffuse axonal damage to their heads.
Diffuse axonal injury refers to the development of damage by rupturing the axons of the brain as a result of strong shaking of the brain. The mechanism by which diffuse axonal injury occurs in the rider's head is explained as follows.

For example, when the right side of the helmet receives an external force due to an impact, the helmet moves to the left. Since the wearer's cervical spine and trunk are not fixed, they also move somewhat to the left. Therefore, most of the directions in which the impact force acts are perpendicular to the outer surface of the helmet. The shock acceleration (this is called translational acceleration) generated by such an external force acting in the vertical direction is measured in the "shock absorption test". The conventional insert liner structure is mainly a countermeasure against the translational acceleration of the impact.

However, when an impact is applied above the helmet and near the crown, the impact point is above the center of gravity of the helmet, so the helmet tries to rotate to the left around the center of gravity. In this way, the impact generates a force that rotates the helmet, that is, a rotational acceleration. Then, the rotation of the helmet is stopped by the lower end of the helmet hitting the wearer's neck or the friction between the helmet and the road surface.

However, the rotational acceleration due to the impact propagates to the wearer's head. Here, if the wearer firmly tightens the agony strap, the wearer's head also stops rotating at the same time as the helmet. Further, when the rotational acceleration propagates to the inside of the wearer's head, a rotational force acts on the brain floating in the cerebral spinal cord in the skull, and the axon connecting the brain and the inside of the skull is torn.

In consideration of the above facts, it is an object of the present invention to obtain a helmet capable of effectively reducing the rotational acceleration of impact and at the same time effectively reducing the translational acceleration.

The helmet according to claim 1 is a helmet provided with an outer cap body made of a hard material and a shock absorbing liner arranged inside the cap body. The shock absorbing liner is a main body liner and a main body liner. A recess provided on the inner side surface, an insert liner fitted into the recess, and a central strut member arranged between the bottom surface of the recess and the bottom surface of the insert liner are provided , and the recess is provided with a helmet. There is an air passage that communicates with the front air inlet and an air passage that communicates with the air outlet behind the helmet.
The insert liner is provided with a ventilation path that communicates the recess and the inner surface of the main body liner (the surface in contact with the wearer's head) .

According to the helmet according to claim 1, the impact applied to the cap body is absorbed by the deformation of the impact absorbing liner arranged inside the outer cap body. An insert liner is fitted in the recess of the main body liner. Then, the central strut member is compressed and deformed by the impact, and the insert liner is tilted. That is, the insert liner moves with respect to the main body liner. At this time, since the wearer's head in close contact with the insert liner also moves, the rotational acceleration does not propagate to the inside of the head. Further, in the recess of the main body liner, there is a space in addition to the insert liner and the central strut member. That is, the same effect as that of the conventional insert liner can be obtained by reducing the volume instead of reducing the density as in the conventional insert liner. In this way, not only the rotational acceleration of the wearer's head but also the translational acceleration can be effectively reduced.
Further, according to the helmet according to claim 1, the outside air taken in from the air inlet on the front surface of the helmet is guided to the concave portion of the main body liner, and further reaches the rear air outlet from the concave portion. This air flow guides the hot air emitted from the wearer's head from the inner surface of the main body liner to the recess through the ventilation path of the insert liner. In addition, the outside air of the recess enters the inner surface of the main body liner. In this way, ventilation in the helmet can be performed well.

The helmet according to claim 2 is the helmet according to claim 1, wherein the shock absorbing liner includes a plurality of other support members arranged around the central support member.

According to the helmet according to claim 2, by providing a plurality of other strut members, even if the wearer's head presses the insert liner when the wearer tightens the ago strap, the strut member is provided together with the central strut member. Supports the insert liner, so the insert liner does not tilt and the helmet does not wobble, so it can be worn in a stable condition.

The helmet according to claim 3 is the helmet according to claim 1 or 2, wherein the central strut member is integrally formed with an insert liner.

According to the helmet according to claim 3, since the central strut member is integrally molded with the insert liner, it is possible to suppress an increase in the number of components of the helmet.

The helmet according to claim 4 is the helmet according to claim 2 or 3, wherein the cross-sectional area of the tip of the other strut member is smaller than the cross-sectional area of the tip of the central strut member, and the central strut The member and the other strut member are integrally molded with the insert liner.

According to the helmet according to claim 4, since the central strut member and other strut members are integrally molded with the insert liner, it is possible to suppress an increase in the number of components of the helmet. Further, when the impact force is transmitted from the bottom surface of the recess to the central strut member and other strut members, the other strut member having a smaller contact area is deformed or damaged first, so that the central strut member is said. Can be prevented from being completely destroyed by impact.
In this way, the insert liner can be reliably tilted by the central strut member.

The helmet according to claim 5 is the helmet according to claim 1 , wherein the air inlet is a rim winding member of an opening on the front surface of the helmet.

According to the helmet according to claim 5 , since the air inlet is a rim winding member of the opening on the front surface of the helmet, the man-hours for providing the air inlet penetrating the cap body can be omitted, and the helmet can be used. It is possible to suppress an increase in the number of component parts.

The helmet according to the present invention has an excellent effect that the rotational acceleration of impact can be effectively reduced, and at the same time, the translational acceleration can also be effectively reduced.

(A) is a side view showing the helmet of this embodiment, and (B) is a front view. It is a perspective view which shows the shock absorption liner disassembled. It is a top view which shows the main body liner. (A) is a perspective view of the insert liner viewed from the user's head side, and (B) is a perspective view of the insert liner viewed from the side opposite to the user's head. It is a perspective view which looked at the insert liner of another form from the side opposite to the head of a user. It is a perspective view which looked at the insert liner of another form from the side opposite to the head of a user. It is a top view which shows the main body liner to which the insert liner is attached. FIG. 5 is a cross-sectional view showing an insert liner and a main body liner cut along the line 6-6 shown in FIG. It is sectional drawing of the main body liner which shows the ventilation inside the main body liner of this embodiment. It is a perspective view seen from the diagonally front side which shows the air inlet of the helmet of this embodiment. It is a front view which shows the air inlet of the helmet of this embodiment. It is a figure explaining the generation of the rotational acceleration, (A) is a view before the impact is applied, (B) and (C) are views which the rider wearing the helmet at the time of the impact is seen from the rear.

As shown in FIG. 8, when the impact F2 is received at a position below the center of gravity (G) of the helmet 10, the neck of the wearer and the body supporting the neck are supported as shown in FIG. 8 (C). The trunk moves. As a result, a force that pushes the helmet 10 sideways acts. That is, translational acceleration occurs. However, when the impact F1 is received at a position above the center of gravity (G) of the helmet 10, a force for rotating the helmet 10 acts as shown in FIG. 8 (B). When the line segment connecting the impact point and the center of gravity (G) is 90 to 45 degrees with respect to the line segment connecting the center of gravity (G) and the apex of the helmet 10, both rotational acceleration and translational acceleration are generated. However, the translational acceleration is larger. Therefore, the impact force can be mitigated even by the conventional measures against the translational acceleration.

Then, as the angle becomes smaller than 45 degrees, the rotational acceleration gradually increases and reaches its maximum at 0 degrees. Therefore, in the present invention, it is preferable to provide the main body liner 16 with a recess 30 (see FIG. 3) described later at a position of 0 to 45 degrees with respect to the line segment connecting the center of gravity (G) and the apex. Further, it is more preferable to provide the recess 30 at a position of 0 to 20 degrees.

First, the configuration of the helmet 10 according to the embodiment of the present invention will be described with reference to FIGS. 1 to 6. The front side in the front-rear direction as seen from the wearer wearing the helmet is indicated by an arrow FR, the right side and the left side are indicated by an arrow RH and an arrow LH, respectively, and the upper side in the vertical direction is indicated by an arrow UP. Further, in the following description, when simply indicating the front-back, left-right, and up-down directions, the front-back, left-right, and up-down directions as seen from the wearer wearing the helmet are used.

As shown in FIG. 1, the helmet 10 of the present embodiment has an outer cap body 12 made of a hard material such as a fiber reinforced resin, and is arranged inside the cap body 12 and inside the cap body 12. It is provided with a shock absorbing liner 14 joined to the surface of the above.

As shown in FIG. 2, the shock absorbing liner 14 includes a main body liner 16 and an insert liner 18 attached to the main body liner 16.
Further, the main body liner 16 is provided with a recess 30 for fitting the insert liner 18.

As shown in FIG. 3, the main body liner 16 is formed by using a foam of synthetic resin, and the main body liner 16 is formed in a dome shape (concave shape) in which one side is open. More specifically, the main body liner 16 is used with a left liner portion 20 and a right liner portion 22 arranged along the user's temporal region, and a rear liner portion 24 arranged along the back of the user's head. It includes a front liner portion 26, which is arranged along the frontal region of the person. Further, the main body liner 16 includes an upper liner portion 28 arranged so as to face the crown of the user. The upper liner portion 28 has an elliptical shape with the front-rear direction as the longitudinal direction and the left-right direction as the lateral direction when viewed from the lower side of the main body liner 16, and the insert liner 18 (see FIG. 2) described later is fitted. The recess 30 is formed. The recess 30 is formed with a vent 32 that communicates with the air inlet in front of the helmet 10 and a vent 34 that communicates with the air outlet behind the helmet 10. Further, in the central portion of the concave portion 30 in the left-right direction and the front-rear direction, the edge portion is circular when viewed from the lower side, and the central convex portion 42 (see FIG. 4A (B)) of the insert liner 18 described later is fitted. A matching central recess 36 is formed. Further, around the central recess 36, three peripheral recesses 38 into which the three peripheral convex portions 44 (see FIG. 4A (B)) of the insert liner 18 described later are fitted are formed. In the present embodiment, two peripheral recesses 38 are formed on the front side of the central recess 36 at intervals in the left-right direction, and one peripheral recess 38 is formed in the central portion in the left-right direction on the rear side of the central recess 36. 38 is formed.

The position of the recess 30 of the main body liner 16 is a conical shape drawn when the line segment connecting the apex of the helmet 10 (see FIG. 8) is tilted 45 degrees around the helmet 10 with the position of the center of gravity of the helmet 10 as the center. It is preferably in an elliptical shape formed by intersecting the outer cap body surface of the helmet 10, and more preferably in the above-mentioned conical shape of 20 degrees. Further, the original thickness of the main body liner 16 when it is assumed that the recess 30 is not provided is preferably 15 to 55 mm, more preferably 35 to 45 mm. At this time, the depth of the recess 30 is preferably 35 mm or less, and more preferably 25 mm or less.

As shown in FIGS. 4A and 4A, the insert liner 18 is formed by using a synthetic resin foam like the main body liner 16. Specifically, the insert liner 18 protrudes upward from the insert liner main body 40 formed in a shallow dish-like shape (concave shape) with one side open and the upper surface of the insert liner main body 40. It is provided with a central convex portion 42 as a central strut member and three peripheral convex portions 44 as other strut members. The lower surface of the insert liner main body 40 is curved in a shape along the crown of the user, and a plurality of grooves 48 for ventilation are formed. Further, a thin-walled portion 50 is arranged at the end of the outer circumference 49 of the insert liner main body 40. The thin-walled portion 50 is thinner than the insert liner main body 40, and is connected to a plurality of grooves 48 and has a substantially U-shaped edge when viewed from the lower side. Is formed. As described above, the lower surface of the insert liner 18 (the surface that contacts the wearer's head) has a symmetrical shape in the front-rear direction and the left-right direction. For industrial production, it is preferably circular or elliptical. Further, the central convex portion 42 is formed in a substantially columnar shape, and projects upward from the central portion in the front-rear direction and the central portion in the left-right direction of the upper surface of the insert liner main body 40. Further, the three peripheral convex portions 44 are formed in a substantially truncated cone shape having an outer diameter smaller than that of the central convex portion 42. In the present embodiment, two peripheral convex portions 44 are formed on the front side of the central convex portion 42 at intervals in the left-right direction, and 1 is formed in the central portion in the left-right direction on the rear side of the central convex portion 42. Two peripheral convex portions 44 are formed.

The insert liner 18 preferably has a thickness of 5 mm or more, preferably 10 to 15 mm, from the lower surface (the surface facing the wearer's head) toward the bottom surface of the recess 30 of the main body liner 16. More preferred. Further, the central convex portion 42 and the peripheral convex portion 44 prevent the insert liner 18 from being pushed by the wearer's head and wobbling when the helmet is worn. However, when an impact is applied to the vicinity of the crown of the helmet, the peripheral convex portion 44 is first deformed, bent, or cracked due to the impact force, but the central convex portion 42 is centered on the insert liner 18. Since it is supported by the insert liner 18, a part of the insert liner 18 falls into the recess 30, and a portion opposite to the recess 30 rises. That is, the insert liner 18 is tilted with respect to the main body liner 16. Subsequently, the depressed peripheral edge portion 44 is lifted by a repulsive force from the bottom surface of the concave portion 30 (the surface of the upper liner portion 28), and the central convex portion and other peripheral convex portions to which the impact is propagated with a delay. 44 deforms, bends, or cracks and sinks into the recess. In this way, the insert liner 18 swings.
The tip of the peripheral convex portion 44 may be conical, as shown in FIG. 4B, so that the contact area of the concave portion 30 with the bottom surface is smaller than that of the central convex portion 42. As shown in FIG. 4C, it may be shaped like a wall (mountain ridge), for example, like the Great Wall of China. Further, the central convex portion 42 and the peripheral convex portion 44 preferably have a circular or elliptical cross section having a diameter of 50 mm or less on the upper surface of the insert liner, and more preferably a diameter of 30 mm or less.

As shown in FIGS. 5 and 6A, the insert liner 18 described above is attached (fixed) to the main body liner 16 in a state of being fitted into the recess 30 of the main body liner 16. More specifically, the insert liner 18 is attached to the main body liner 16 in a state where the central convex portion 42 and the three peripheral convex portions 44 of the insert liner 18 are engaged with the central concave portion 36 and the three peripheral concave portions 38 of the main body liner 16. It is fixed. In the present embodiment, since the adhesive is interposed between the central convex portion 42 of the insert liner 18 and the central concave portion 36 of the main body liner 16, the insert liner 18 can be removed from the main body liner 16 even if the helmet is removed. It is designed so that it will not come off.

Further, in a state where the insert liner 18 is fixed to the main body liner 16, a gap is formed between the upper surface of the insert liner main body 40 of the insert liner 18 and the main body liner 16. Since the insert liner 18 swings (swings and moves with respect to the main body liner), the gap formed between the outer peripheral 49 of the insert liner 18 and the inner wall of the recess 30 is preferably 10 mm or less. It is more preferably 3 mm to 7 mm. Further, the central convex portion 42 of the insert liner 18 and the three peripheral convex portions 44 can be made of different members from the insert liner 18 and the main body liner 16, but the central convex portion can be manufactured industrially. It is conceivable that the 42 and the three peripheral convex portions 44 are integrally molded on the bottom surface of the insert liner 18, or integrally molded on the bottom surface of the concave portion 30 of the main body liner 16.

Further, the thin portion 50 covers the space between the outer peripheral 49 of the insert liner 18 and the inner wall of the recess 30, but when the insert liner 18 swings, it is pressed against the inner wall of the recess 30 and is easily deformed or deformed. It will break and will not interfere with the swing.

(Action and effect of this embodiment)
Next, the operation and effect of this embodiment will be described.

As shown in FIGS. 1 and 2, according to the helmet 10 described above, the impact absorbing liner 14 arranged inside the outer cap body 12 is deformed, so that the impact applied to the outer cap body 12 is applied to the outer side. Is absorbed. Further, as shown in FIGS. 5 and 6, the insert liner 18 is fitted in the recess 30 of the main body liner 16. Then, the central convex portion 42 and the three peripheral convex portions 44 are deformed to reduce the translational acceleration, and the insert liner is moved (swinged) with respect to the main body liner 16 to attach the helmet 10. The rotational acceleration of the user's head can be effectively reduced.

More specifically, since a gap is provided between the insert liner 18 and the recess 30, the ups and downs phenomenon occurs (that is, swings) instantly as soon as the impact is transmitted to the insert liner 18. When the insert liner 18 sways in this way, the wearer's head, which is in close contact with the insert liner 18, also swings and sways. That is, even if the rotation of the helmet 10 is stopped after the rotational force is generated in the helmet 10 by the impact, the head of the wearer inside the helmet 10 continues to move, so that the rotational acceleration due to the impact is propagated to the inside of the head. It can be absent or reduced.

In order to maximize the swing effect due to the ups and downs (swing) of the insert liner 18, it is necessary to incline the center point of the insert liner 18. Therefore, it is preferable to provide the central convex portion 42 at the center point of the bottom surface of the insert liner 18 and arrange the peripheral convex portion 44 around the central convex portion 42. Further, if the peripheral convex portion 44 is made to have a shape that is more easily deformed than the central convex portion 42, the peripheral convex portion 44 is deformed by the impact, so that the insert liner 18 is encouraged to tilt around the central convex portion 42. be able to.

Here, the test result of the impact test of the helmet 10 will be described.

(Test result of impact test)
A helmet 10 was put on the human head model and dropped on a steel anvil from a height of 2.5 m, and the rotational force generated by the impact at that time was measured by an angular velocity meter. The impact points were three points: the vicinity of the crown of the helmet 10, the frontal region when the helmet 10 was tilted forward by 45 degrees, and the left head when the helmet was tilted 45 degrees to the left.

As is clear from Table 1, when the swinging insert liner 18 like the helmet 10 of the present embodiment is used, the rotational acceleration is clearly reduced as compared with the conventional insert liner. The conventional insert liner is a type in which the insert liner does not swing with respect to the main body liner.

Further, in the helmet 10 of the present embodiment, as shown in FIGS. 4A (B) and 6, the insert liner 18 is in a stable state by providing three peripheral convex portions 44 in addition to the central convex portion 42. Can be maintained at.

Further, when only the central convex portion 42 is provided, it is uncomfortable to wear because the wearer is unstable only by wearing the helmet 10 (because the insert liner 18 is easily tilted with respect to the main body liner 16). Further, when the translational acceleration of the impact is too large, the central convex portion 42 cannot support the wearer's head and is easily crushed, and the insert liner 18 may drop substantially parallel to the concave portion 30. is expected. That is, in this case, the ups and downs phenomenon of the insert liner 18 does not occur. Therefore, in the present embodiment, in addition to the central convex portion 42, the force for supporting the insert liner 18 can be reinforced by providing three peripheral convex portions 44 having a cross-sectional area of the tip thereof smaller than that of the central convex portion 42. Then, any of the three peripheral convex portions 44 is deformed or refracted to buffer the translational acceleration, and further, the insert liner 18 causes an ups and downs phenomenon to buffer the rotational acceleration.

Further, in the present embodiment, as shown in FIGS. 3, 5 and 6B, the ventilation holes 32 and 34 as ventilation passages communicating with the air inlet in front of the helmet 10 and the air outlet in the rear of the helmet 10. The insert liner 18 is provided with a notch 52 that communicates the recess 30 with the wearer's head. The outside air taken in from the air inlet on the front surface of the helmet is introduced into the recess 30 through the vent 32 formed in the recess 30 of the main body liner 16, and is discharged from the air outlet through the vent 34. A flow occurs. Therefore, the hot air emitted from the wearer's head is guided to the recess of the main body liner through the notch 52 (communication portion). Further, a part of the outside air introduced into the recess 30 reaches the wearer's head through the notch 52 (communication portion). In this way, the ventilation performance in the helmet 10 can be improved. That is, the hot air inside the helmet 10 is discharged, and comfort can be provided to the wearer. Further, by providing the ventilation holes 32 and 34 communicating with each other in the front and rear of the helmet 10 on the crown including the recess 30, the main body liner 16 can more easily absorb the translational acceleration due to the impact.
In the present embodiment, the notch 52 is provided as a communication portion for communicating the wearer's head and the recess 30, but the present invention is not limited to this, and a plurality of communication holes penetrating the insert liner 18 are provided. Is also good.

Further, in the insert liner 18 of the present embodiment, a thin-walled portion 50 whose thickness is set to be thinner than the thickness of the central portion 46 is arranged at the end of the outer peripheral 49 of the insert liner main body 40. In addition to this, a plurality of notches 52 are formed in the thin portion 50. The notch 52 reduces the rigidity of the thin portion 50. As a result, when an impact is applied to the helmet 10, the thin portion 50 is easily deformed or damaged, so that the insert liner does not interfere with the movement (swing). Then, in the present embodiment, a plurality of peripheral convex portions 44 are arranged and reinforced around the central convex portion 42 so that the central convex portion 42 and the like are crushed and the insert liner 18 swings without being depressed in the concave portion 30. ..

Further, in the present embodiment, as shown in FIGS. 7A and 7B, an air inlet is provided in the edge winding member 54 of the opening on the front surface of the helmet, and the taken-in outside air is divided into two, one of which is the main body liner 16. One that travels through the outer surface of the main body to reach the recess 30 through the vent 32, and the other one that travels along the inner surface of the main body liner 16 to the ventilation groove 48 provided on the lower side of the insert liner 18. Be taken. In this way, the number of parts for the air inlet can be reduced, and the assembly man-hours can be reduced.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and can be modified in various ways other than the above within a range not deviating from the gist thereof. Of course.

10 Helmet 12 Cap body 14 Shock absorption liner 16 Body liner (main liner)
18 Insert liner 30 Recess 32 Vent hole (vent)
34 Vents (vents)
40 Insert liner main body 42 Central convex part (central support member)
44 Peripheral convex part (other strut members)
48 Ventilation groove 49 Outer circumference of insert liner body 50 Thin wall 52 Notch (communication part)
54 Edge winding member

Claims (5)

In a helmet with an outer cap made of hard material and a shock absorbing liner located inside this cap.
The shock absorbing liner is a center arranged between a main body liner, a recess provided on the inner side surface of the main body liner, an insert liner fitted in the recess, and a bottom surface of the recess and the bottom surface of the insert liner. With a support member ,
The recess is provided with an air passage that communicates with the air inlet in front of the helmet and an air passage that communicates with the air outlet behind the helmet.
The insert liner is a helmet provided with a ventilation path for communicating the recess and the inner surface of the main body liner (the surface in contact with the wearer's head). The helmet according to claim 1, wherein the shock absorbing liner includes a plurality of other strut members arranged around the central strut member. The helmet according to claim 1 or 2, wherein the central strut member is integrally molded with an insert liner. The cross-sectional area of the tip of the other strut member is formed to be smaller than the cross-sectional area of the tip of the central strut member, and the central strut member and the other strut member are integrally formed with the insert liner. The helmet according to claim 2 or 3. Said air inlet is a helmet according to claim 1, wherein is a Enmaki member of the opening of the helmet front.